1=pod 2 3=head1 NAME 4 5RSA_check_key - validate private RSA keys 6 7=head1 SYNOPSIS 8 9 #include <openssl/rsa.h> 10 11 int RSA_check_key(RSA *rsa); 12 13=head1 DESCRIPTION 14 15This function validates RSA keys. It checks that B<p> and B<q> are 16in fact prime, and that B<n = p*q>. 17 18It also checks that B<d*e = 1 mod (p-1*q-1)>, 19and that B<dmp1>, B<dmq1> and B<iqmp> are set correctly or are B<NULL>. 20 21As such, this function can not be used with any arbitrary RSA key object, 22even if it is otherwise fit for regular RSA operation. See B<NOTES> for more 23information. 24 25=head1 RETURN VALUE 26 27RSA_check_key() returns 1 if B<rsa> is a valid RSA key, and 0 otherwise. 28-1 is returned if an error occurs while checking the key. 29 30If the key is invalid or an error occurred, the reason code can be 31obtained using L<ERR_get_error(3)|ERR_get_error(3)>. 32 33=head1 NOTES 34 35This function does not work on RSA public keys that have only the modulus 36and public exponent elements populated. It performs integrity checks on all 37the RSA key material, so the RSA key structure must contain all the private 38key data too. 39 40Unlike most other RSA functions, this function does B<not> work 41transparently with any underlying ENGINE implementation because it uses the 42key data in the RSA structure directly. An ENGINE implementation can 43override the way key data is stored and handled, and can even provide 44support for HSM keys - in which case the RSA structure may contain B<no> 45key data at all! If the ENGINE in question is only being used for 46acceleration or analysis purposes, then in all likelihood the RSA key data 47is complete and untouched, but this can't be assumed in the general case. 48 49=head1 BUGS 50 51A method of verifying the RSA key using opaque RSA API functions might need 52to be considered. Right now RSA_check_key() simply uses the RSA structure 53elements directly, bypassing the RSA_METHOD table altogether (and 54completely violating encapsulation and object-orientation in the process). 55The best fix will probably be to introduce a "check_key()" handler to the 56RSA_METHOD function table so that alternative implementations can also 57provide their own verifiers. 58 59=head1 SEE ALSO 60 61L<rsa(3)|rsa(3)>, L<ERR_get_error(3)|ERR_get_error(3)> 62 63=head1 HISTORY 64 65RSA_check_key() appeared in OpenSSL 0.9.4. 66 67=cut 68